30 Bottled Water Samples Vastly Varied in Taste, Texture and Value-for-money Convenient but Not Environmentally Friendly Think Twice When Consuming

The body loses water more readily on hot days, so it is vital to stay hydrated in the scorching summer heat, especially those working or exercising outdoors. For many people, bottled water is a convenient way to replenish lost moisture for the body. The Consumer Council tested 30 bottled water samples on the market and did not find any harmful substances that exceeded the relevant standard levels of the World Health Organization (WHO), so consumers can drink with confidence.

However, the price varied considerably among samples. The average unit price per litre for natural mineral water samples (sparkling or still) was $20.8, almost 3 times that of distilled water and purified drinking water (without added minerals) samples ($7.02). As many consumers believe that natural mineral water has a higher mineral content, they would opt for this type of water due to health benefits or taste and texture, despite the higher price. Nevertheless, the Council’s test revealed that although the total dissolved solids (TDS) content of all natural mineral water samples was relatively higher, one of the samples only contained 19mg/l, which was even lower than that of 1 purified drinking water sample (24mg/l). TDS content could be used as one of the aspects for analysing the taste, colour and mineral content impacting drinking water. Among all the natural mineral water samples, the TDS level detected was varied, ranging from 19mg/l to 657mg/l.  When solely considering the aspect of value for money, cheaper non-natural mineral water or even potable boiled tap water may be better choices. Furthermore, although bottled water is convenient and comes in a vast selection, it poses profound impact to the environment as the production of plastic bottles depletes large amounts of the earth’s resources. The Council calls on consumers to try and change their lifestyle habits and bring their own reusable bottles, so as to reduce waste at its source and practice sustainable consumption.

The Council purchased 30 samples of more common bottled water from different retailers for the test, ranging from 500ml to 5,500ml in volume, and $3.6 to $114.7 in average price per litre. The samples included 3 distilled waters, 3 purified drinking waters, 1 distilled water added with minerals, 2 mineralised purified waters, 17 natural mineral waters, and 4 sparkling natural mineral waters. The tests reviewed the product safety and quality of the bottled water samples with reference to relevant legislation in Hong Kong, United States (US) and the European Union (EU), as well as the WHO’s guidelines and the Codex Alimentarius standard.

All Samples Passed Safety Tests

Natural Mineral Water Cost Almost Double

To ensure all bottled water samples were safe for drinking, the samples were tested for their levels of nitrite and nitrate[1], disinfectants residue and disinfection by-products[2], plasticisers and bisphenols[3], microorganisms[4], microplastics[5] and metallic contamination[6]. Results indicated that none of the above exceeded the standard levels. Some samples were detected with heterotrophs, but levels did not exceed the US Drinking Water Regulations. Although most samples were detected with 1 to 5 types of metallic contaminants, detected levels did not exceed the maximum level set out in the Food Adulteration (Metallic Contamination) Regulations, and all test results were satisfactory.

The average price per litre of distilled water and purified drinking water samples was $7.02, that for distilled water added with minerals and mineralised purified water samples was $7.57, while that for natural mineral water samples (both sparkling and still) was $20.8. Overall, natural mineral water samples were the highest in price, almost threefold that of the other types of water. However, as many people believe that natural mineral water is richer in mineral content, they are still willing to pay the higher price.

“Acceptability Aspects” Reflect that Water Has Flavour and Texture

Total Dissolved Solid Content May Affect the “Taste”

While water is generally classified as colourless and tasteless, the TDS content could be used as one of the acceptability aspects for analysing the taste and colour impacting drinking water. The higher the TDS level, the higher the dissolved solid content in water, including the mineral content. A study by the WHO described drinking water with a TDS level between 25mg/l and 50mg/l as having a “flat and insipid taste”.

The test revealed that distilled water and purified drinking water samples generally had lower TDS levels. 3 samples of distilled water and 2 samples of purified drinking water were not detected with TDS at all, while 3 distilled water and purified drinking water samples that claimed to be added with minerals were detected with TDS levels from 22mg/l to 38mg/l. Among the 21 samples of natural mineral water tested, the TDS level detected ranged from 19mg/l to 657mg/l, with the lowest TDS content even lower than a sample of purified drinking water (24mg/l). Although natural mineral water contains natural minerals, the content varied considerably among samples and their retail price also varied notably. Thus, the results reflected that there is no necessary correlation between the retail price and TDS content of a product.

According to the WHO’s report, under most circumstances, humans can obtain mineral elements from their daily diet, and if they cannot obtain sufficient minerals through this means, drinking water can still supplement some of the dietary minerals required. However, the Council reminds consumers that renal disease patients or individuals with weaker renal functions may not be able to discharge excess minerals from their body, thus they should seek medical advice before consuming mineral water or mineralised water.

Calcium Content of Tap Water at 14mg/l Just Second to Mineral Water

An Economic and Eco-friendly Choice

Many consumers purchase bottled water not only because of convenience, but also due to safety considerations and better assurance of the water quality. According to data from the Water Supplies Department (WSD), tap water in Hong Kong is safe and potable. As for the water charges, based on the current tariff structure, each 100 cubic metre of potable water would cost $262, equivalent to a cost of $0.00262 per litre. On the other hand, distilled water and purified drinking water (without added minerals) samples cost $7.02 per litre on average, which is 2,679 times that of fresh water. In comparison, tap water is much more economical. In terms of the calcium content, according to the WSD’s Drinking Water Quality Report for the period from October 2022 to September 2023, drinking water in Hong Kong has an average calcium content of 14mg/l, only second to the natural mineral water samples (3.1mg/l to 210mg/l), but higher than the samples of distilled water with minerals and mineralised purified water (0.49mg/l to 4.1mg/l) and distilled water and purified drinking water (0mg/l to 0.08mg/l). Health reasons and personal preferences aside, generally speaking, boiled tap water could be a safe, healthy, economical and environmentally friendly choice for consumers.

Additionally, the increased consumption of plastic bottled water could aggravate the problem of plastic pollution. The plastic bottles of bottled water are usually for single use only, and many end up as waste in the landfills, often taking several hundred years to degrade. During the degradation process, plastic would break down into microplastics and drift into the oceans, affecting marine life and posing profound impact on the environment. As some of these microplastics enter the food chain, humans eventually suffer the consequences of their own actions. Furthermore, plastics are made from non-renewable fossil fuels which must be mined. Even when the plastic bottles are recycled appropriately, it could only save parts of the energy used in the production of plastic bottles. Therefore, consumers should attempt to change their lifestyle habits and cut waste at its source by buying less bottled water, and reducing environmental pollution.

Consumers could refer to the following recommendations should they need to consume or purchase bottled water:

• As the urinary system of infants is not fully developed, parents should avoid preparing infant formula with mineral water. If using bottled distilled water to mix milk formula, the water should be boiled beforehand to eliminate the harmful bacteria in the milk powder;
• Despite all samples passing the test for heterotrophic plate count, some samples were detected with trace amounts of colony. For safety reasons, individuals with a weaker immune system should avoid drinking undistilled bottled water, or boil it before drinking;
• Renal disease patients or individuals with weaker renal functions may not be able to discharge excess minerals from their body, thus they should seek medical advice before consuming mineral water or mineralised water;
• Bottled water should be refrigerated after opening and consumed as soon as possible;
• Unless otherwise indicated, the plastic bottles of bottled water are generally for single use only and are not suitable for repeatedly holding other beverages.